code: def test_pytorch_training_warning(request: Any) -> None:
      backend = request.config.option.backend
      if backend != "pytorch":
          pytest.skip()
  
      import torch
  
      class Model(torch.nn.Module):
          def forward(self, x: torch.Tensor) -> torch.Tensor:
              return x
  
      model = Model().train()
      bounds = (0, 1)
      with pytest.warns(UserWarning):
          fbn.PyTorchModel(model, bounds=bounds, device="cpu")
  
file_path: foolbox/tests/test_models.py
imports: from typing import Tuple, Any
  import pytest
  import eagerpy
  import numpy
  import copy
  import foolbox
label_desc: Use image node_id 4 for calling a global function with example usage: test_pytorch_training_warning(request) and returns: x